Helmets for head protection must fit a variety of head shapes and sizes. Once a helmet is adapted to a particular wearer's head by customizing or adjusting cushions and pads within the shell, straps attached to opposite sides are secured at the wearer's neck or chin to keep the helmet from falling off. Several refinements in retention systems for helmets, particularly mountain bike helmets, have been made in recent years. One such refinement involves an articulated member at the rear of the helmet, which contacts the wearer's head beneath the occipital region and thereby improving the stability of the helmet on the head; see, e.g., U.S. Pat. No. 5,659,900. This articulated member is retained elastically to the shell of the helmet, while a mechanically separate chinstrap is used to hold the helmet on the rider's head. This system improves the stability of the helmet, but requires the wearer to release or stretch the elastic strap holding the articulated member each time the helmet is put on the wearer's head. In other configurations, the articulated member is positioned by a spring element against the back of the wearer's neck; see, e.g., U.S. Pat. No. 6,425,142. In all such cases, the fit is not especially secure and/or is adjusted separately from the chinstrap each time the helmet is worn, an inconvenient operation.
Another approach utilizes a stabilizer mounted in the rear of the helmet to engage the nape of the neck of the wearer; see, e.g., U.S. Pat. No. 5,794,272. Secured by the helmet retention system, the stabilizer is attached via a strap to the chinstrap at a point below the wearer's ear. This allows a wearer to adjust the straps for his or her particular head shape once, and subsequently attach the helmet only by means of the chinstrap. When the chinstrap is released, the stabilizer is able to move rearward, facilitating removal of the helmet. When the helmet is to be worn again it is placed on the head with the stabilizer in the released position, and the chinstrap is then attached to secure both helmet and stabilizer.
While this approach requires one adjustment and then a single attachment action for repeat use, the adjustment for different fits is not easy. Moreover, the stabilizer is secured by connecting its strap to the chinstrap below the ear. This configuration is inconsistent with the most desirable tensioning direction of the stabilizer, namely, forward and upward against the head: pulling downward against the chinstrap is not the preferred direction, and the attachment point below the ear provides limited resistance to forces tending rotate and dislodge the helmet during use.